One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6,9,8)(7,11,12,10)(13,14)(15,19)(16,17)(18,20)(22,26)(24,27)(6,8)(7,12)(14,16)(18,19)(22,26)(23,28) involution — undirected(13,15)(14,18)(16,19)(17,20)(21,22,25,26)(23,27,28,24)(1,3,4,2)(5,7,9,12)(6,10,8,11)(13,15)(14,18)(16,19)(17,20)(21,23)(22,27)(24,26)(25,28)(5,8,9,6)(7,11,12,10)(13,16,17,14)(15,19,20,18)(21,24,25,27)(22,23,26,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.